Track brakes: rebuild & add cooling... or upgrade?

[dcaron9999]

Originally Posted by odj

Well, the brakes are on, bled, and bedded. Even with the street pads, they're already enough to lock up the front 225 ZIIs.

Gotta screw around with INPA this afternoon to see if I can cycle ABS. I did hit ABS a couple times when bedding the pads, and pedal was noticeably softer after doing so.

I noticed this exact behavoir myself. I come out of the brake bleed job with a firm pedal, and after I hit ABS during test runs, my brake pedal sinks a bit lower.

Did you get to cycle the ABS pump, and bleed again? I tried a few combinations myself with my Cobb AP3 (clear codes, reflash of custom map, clear ECU), but dont think it helped. Also tried running the engine while on floor jacks, shifting in 1st gear, and triggering ABS.

[wjk_glynn]

Follow up...

Originally Posted by wjk_glynn

I don't know, but if I can think of a way to cycle the ABS pump I will.

I asked the original shop and they said they do (as standard practice) cycle the ABS pump(s). But rather than give them another (i.e. third) go, I instead went to Dinan Service in Campbell, and asked them to do a complete brake fluid flush (with Motul 660) and explicitly cycle the ABS pump(s).

The end result is that I think that 99.5% of the variation is gone, and the last 0.5% could easily be down to my hypochondria.

However it's not the 'rock hard' setup that others have experienced with the ST60. But it's not a disaster either. It's acceptable.

Karl.

PS: As a side note, I installed Cobb V2 on the car today and it didn't appreciably improve things. C'est la vie...

[Focusedintntions]

Sounds like a lot of what you guys are experiencing is pad knockback as well.....I got it really bad on my 135 with the larger racing brake rotors after long straights. The larger the rotor the more chance to get knock back. And if you have a rotor with any sort of crossed drilling or cooling holes you'll also get pad knock back. Very common thing. If you watch a lot of race cars you'll see them lightly tap the brakes to re seat the pads to the rotor after long straights

[Focusedintntions]

FWIW OP if you haven't decided already. In the long run it's cheaper to do a bbk than rebuild. You'll still want to duct, but you'll get longer life out of the consumables with a bbk, and b/c the pad design is standard for the stoptechs, you'll have a bigger selection of pads and they're much cheaper

[ShortShift]

I was thinking of doing a rebuild with Racing Brake parts but found a great deal on F30 m performance front brakes that i plan to have installed along with endless me20 pads all around. Will updates once i have it all done.

My current setup is

Hawk Hp+ all around
powerslot slotted rotors (aka stoptech)
bimmerworld ss lines
endless rf650
f30 front brake ducts (not sure if these helped or not but got them as a gift so why not install)

brakes still fade at almost all socal tracks. not the most confidence inspiring setup so im hoping the 370mm bbk will help

Aaron

[2PUTT]

Originally Posted by ShortShift

I was thinking of doing a rebuild with Racing Brake parts but found a great deal on F30 m performance front brakes that i plan to have installed along with endless me20 pads all around. Will updates once i have it all done.

My current setup is

Hawk Hp+ all around
powerslot slotted rotors (aka stoptech)
bimmerworld ss lines
endless rf650
f30 front brake ducts (not sure if these helped or not but got them as a gift so why not install)

brakes still fade at almost all socal tracks. not the most confidence inspiring setup so im hoping the 370mm bbk will help

Aaron

Not a huge Hawk pad fan. My current setup has been pretty solid. Castrol SRF Fluid with Porterfield R4 pads. FYI - hawk HP Plus is more of a street/auto cross pad. Not really recommended for heavy track use since the Friction level falls when temperatures go up. Rest of my brakes setup is stock.

[wjk_glynn]

Originally Posted by Focusedintntions

Sounds like a lot of what you guys are experiencing is pad knockback as well.....I got it really bad on my 135 with the larger racing brake rotors after long straights. The larger the rotor the more chance to get knock back...

The shop that installed the ST60 said the same thing to me, but I've had difficulty believing you'd see knockback in around town driving.

But maybe I'm missing something.

My understanding is/was that knockback is caused by flexing in the hub/rotor assembly, altering 'effective' run-out, which taps the pads back.

But your comment that it happens "after long straights" implies there's other mechanisms at play.

Can you explain?

Thanks.

Karl.

[slonik]

i think my question would be appropriate in this topic.

i'm not so expert in bmw models, but may be somebody knows, which hub can be used on e82 as an upgrade? i'm asking cause i saw, that oem hub has a lot of play.


little explanation .

we've used square setup on our e82 (275/275) last season, and at first 1000 km i've noticed, that one of the front wheels have noticeable free play - there are really bad roads here in russia, and after hard winters we have very noticeable tracks on the road surface, so car on 275 wheels pulls really hard on different sides (depends on slope). in some cases i can heard that the pads makes some noise (brake pedal not pushed), and sounds can disappearing, if i change my position on the road and the car pulls less (it's all about road surface).
so, first i thought, that hub bearing was died, and i've changed it with new oem one. and, my surprise, but nothing was changed! same wheel playing (with brake rotor of course) on the hub bearing.

i think that this issue can add a lot for brakes overheating on track, where hub bearings has a lot more loads. we had no problems with overheating, only thanks our brake system, which is much bigger, than the stock one .

on our other track prepared cars with similar wide square setup nothing like this. on m3 e46 i saw similar problem only on very tired hub bearing, and after changing it, problem gone away.
ps something like this

[_Ryan_]

Originally Posted by slonik

i think my question would be appropriate in this topic.

i'm not so expert in bmw models, but may be somebody knows, which hub can be used on e82 as an upgrade? i'm asking cause i saw, that oem hub has a lot of play.


little explanation .

we've used square setup on our e82 (275/275) last season, and at first 1000 km i've noticed, that one of the front wheels have noticeable free play - there are really bad roads here in russia, and after hard winters we have very noticeable tracks on the road surface, so car on 275 wheels pulls really hard on different sides (depends on slope). in some cases i can heard that the pads makes some noise (brake pedal not pushed), and sounds can disappearing, if i change my position on the road and the car pulls less (it's all about road surface).
so, first i thought, that hub bearing was died, and i've changed it with new oem one. and, my surprise, but nothing was changed! same wheel playing (with brake rotor of course) on the hub bearing.

i think that this issue can add a lot for brakes overheating on track, where hub bearings has a lot more loads. we had no problems with overheating, only thanks our brake system, which is much bigger, than the stock one .

on our other track prepared cars with similar wide square setup nothing like this. on m3 e46 i saw similar problem only on very tired hub bearing, and after changing it, problem gone away.
ps something like this

I'm interested, I've had this happen too.

[slonik]

f30 hub?

they looks similar. another question, where is guarantee, that it isn't the same quality, with a lot of play...

[Rikx1M]

So did OP ever install his BBK? Results?

[odj]

Originally Posted by Rikx1M

So did OP ever install his BBK? Results?

Months later...

I did. I ended up picking up a Stoptech Trophy BBK for the front. On the track I ran SR34 pads front and PFC08s on the stock rear brakes and some Castrol SRF fluid.

The difference was incredible. No fade at all (even after the 135+ mph main straight at VIR), and the stopping power is just nutty.

The only problem I have with the brakes is that everything for them is EXPENSIVE. Like stupid expensive. I'm a big fan of the PFC08 pads, but they were ~$550 just for the fronts, and my plan to have separate rotors for street and track were crushed when I realized they were almost $700 for a pair. I know, I know... pay to play and all that, but still...

Two things worth noting:

1. Don't use *any* sort of wheel cleaner on the brakes. Not even a basic solution (somewhere in the instructions it says to avoid acidic cleaners). It'll smear the clear anodizing finish. Ask me how I know.
2. These brakes are the most finicky I've ever used in terms of proper bedding. I followed the included directions to a T and still ended up with deposits. On street as well as track pads. So I "cleaned" them by doing 2 or 3 hard slows from 70 with the track pads cold, and then re-bed 2-3 intervals increasing start speed from ~50 to ~70. That worked.

Now I've found some signs of melting/cracking in the stock rear dust boots, so I think I'll have to rebuild them after this year's track season is done with. I've also thought about trimming down the Ti shims I got for the stock fronts to fit the rear pads. Gotta line them up and see if that'll work.

On the bleeding front, "driving" the car with all four corners on jack stands does indeed activate ABS, and has enabled me to get a much better (but still not perfect, dammit) bleed.

[Bullitt]

^ Thanks for the update. Good to hear the BBK is a significant improvement. The pads and rotors are indeed expensive, but I heard that they'll last at least 2-3x times longer than the stock brakes so it comes out cheaper in the long run.

[Focusedintntions]

Originally Posted by wjk_glynn

The shop that installed the ST60 said the same thing to me, but I've had difficulty believing you'd see knockback in around town driving.

But maybe I'm missing something.

My understanding is/was that knockback is caused by flexing in the hub/rotor assembly, altering 'effective' run-out, which taps the pads back.

But your comment that it happens "after long straights" implies there's other mechanisms at play.

Can you explain?

Thanks.

Karl.

Karl,
In a really basic sense....your rotors are just giant fans. On really long fast straights just the air being pushed out of cross drilled rotors can push back the pads some. Or just even the air just coming out the top of the vanes as it comes through the caliper can do it.

[davidwarren]

http://www.e90post.com/forums/showthread.php?t=1287364

Here is how I added ducts.

[wjk_glynn]

Originally Posted by wjk_glynn

The end result is that I think that 99.5% of the variation is gone, and the last 0.5% could easily be down to my hypochondria.

6+ months later and I've come to the conclusion that the variability is effectively gone.

Since the ABS pump cycling by Dinan, it's just gotten better to where I can say the pedal pressure/response is now consistently good.

Originally Posted by odj

...I ended up picking up a Stoptech Trophy BBK for the front.
...
The only problem I have with the brakes is that everything for them is EXPENSIVE.

Does the Trophy kit use the same rotors/pads as the ST60?

If so, and not saying these are cheap, but these prices aren't too outrageous:

Front Rotor - Left - $260 - https://www.amazon.com/StopTech-31-7.../dp/B00FJ0EPJI
Front Rotor - Right - $270 - https://www.amazon.com/StopTech-31-7...NP09T1HM5FET67

Front Pads - StopTech "Sport" - $85 - https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Front Pads - StopTech SR32 Race - $257 - https://www.amazon.com/Centric-332-8...+332.8011.18.0
Front Pads - StopTech SR34 Race - $255 + shipping - http://www.redline360.com/stoptech-334.8011.18.0

Originally Posted by odj

These brakes are the most finicky I've ever used in terms of proper bedding. I followed the included directions to a T and still ended up with deposits. On street as well as track pads. So I "cleaned" them by doing 2 or 3 hard slows from 70 with the track pads cold, and then re-bed 2-3 intervals increasing start speed from ~50 to ~70. That worked.

Thanks for the tip.

Originally Posted by Focusedintntions

In a really basic sense....your rotors are just giant fans. On really long fast straights just the air being pushed out of cross drilled rotors can push back the pads some. Or just even the air just coming out the top of the vanes as it comes through the caliper can do it.

Ahhh...

Originally Posted by davidwarren

http://www.e90post.com/forums/showthread.php?t=1287364

Here is how I added ducts.

Brilliant.

Karl.

[jafo1701]

Update on the racing brake kit. After the whole seal debacle, I got new seals from rock auto and racing brake was kind enough tp send me high temp dust boots. Finally got back on the track, while the pistons are holding up fine, even the high temp dust boots can't take the heat. They are starting to crack after six, twenty minute track sessions. I guess I'm just generating too much heat on the stock size rotors. I hate rebuilding my calipers every year, thinking maybe going with a bbk soon, at least for the fronts. Rears are holding up with the high temp boots.

[Faulal]

Originally Posted by jafo1701

Update on the racing brake kit. After the whole seal debacle, I got new seals from rock auto and racing brake was kind enough tp send me high temp dust boots. Finally got back on the track, while the pistons are holding up fine, even the high temp dust boots can't take the heat. They are starting to crack after six, twenty minute track sessions. I guess I'm just generating too much heat on the stock size rotors. I hate rebuilding my rotors every year, thinking maybe going with a bbk soon, at least for the fronts. Rears are holding up with the high temp boots.

You may have stated this before in the thread, but what pads are you running?

[jafo1701]

Originally Posted by Faulal

You may have stated this before in the thread, but what pads are you running?

Carbotech XP12s in front and XP10s in the rear.

[lakefront]

Guy on the For Sale forum has been trying to sell a year old Stoptech F/R Trophy kit for over a month now. Price down to $3000 shipped with extra set of pads. Can't believe nobody has jumped on this. Solve all brake overheating problems with one purchase.....
I bought the same kit used earlier this year (for a little more money) and love it!

[spxxx]

Originally Posted by lakefront

Guy on the For Sale forum has been trying to sell a year old Stoptech F/R Trophy kit for over a month now. Price down to $3000 shipped with extra set of pads. Can't believe nobody has jumped on this. Solve all brake overheating problems with one purchase.....
I bought the same kit used earlier this year (for a little more money) and love it!

If I wasn't about to buy a house I would be ALL over it ...

[jafo1701]

Originally Posted by Bullitt

I personally have not tried nor verified the following procedure yet, but it seems to have worked for a fellow member who accidentally ran his brake system dry and needed to bleed the ABS system:

"Put it up on 4 jack stands and drive the car in gear. Do not turn off traction control or anything. The car will not go above 15 mph and you'll hear the abs pump cycle. (The car will sound really weird) Once you do like 5 "pulls" for approx 10-12 seconds each pull, rebleed the brakes in the proper bleeding order. I did the whole cycle 3 times. It worked for me and I have my pedal back no problem."

Reference: http://www.1addicts.com/forums/showp...0&postcount=36

I tried this when all my brake fluid drained after my seals failed over the winter. While it did help it never completely made my brakes feel right. Took it to an Indy shop, paid an hour's labor. Now my brakes feel great again. My suggestion, try it. If it doesn't feel right. Pay the hours labor and get it done right.